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File::Glob sometimes returns pattern if no match, regardless of GLOB_NOCHECK
From @epa
Created by @epa
The documentation for File::Glob states
File::Glob::bsd_glob() implements the FreeBSD glob(3) routine,
The POSIX defined flags for bsd_glob() are: ... GLOB_NOCHECK If the pattern does not match any pathname, then bsd_glob() returns a list consisting of only the pattern.
This implies that the behaviour of returning the pattern back on no match is governed by this flag. If the flag is not given, then a pattern which matches no filenames would be expected to return an empty list. But in fact this sometimes happens and sometimes not:
% mkdir new
% cd new
% perl -MFile::Glob -E 'say File::Glob::bsd_glob("x")'
x
% perl -MFile::Glob -E 'say File::Glob::bsd_glob("x", File::Glob::GLOB_NOCHECK())'
x
% perl -MFile::Glob -E 'say File::Glob::bsd_glob("x*")'
% perl -MFile::Glob -E 'say File::Glob::bsd_glob("x*", File::Glob::GLOB_NOCHECK())'
x*
The first of the four cases above is odd. GLOB_NOCHECK was not specified; the pattern matched no files; and yet the pattern is being returned back.
While this is consistent with Perl's builtin glob(), it seems inconsistent with File::Glob's documentation and with the FreeBSD glob(3) it purports to implement - at least as far as I can tell from for example <https://www.freebsd.org/cgi/man.cgi?query=glob&sektion=3>.
I suggest fixing the behaviour of bsd_glob() to be as documented - so a pattern with no matches returns nothing, unless GLOB_NOCHECK is given, in which case the pattern itself is returned as the only match.
(That does not imply that Perl's builtin glob() should change its behaviour, since glob() is defined to do what /bin/csh would do. Currently, glob() is implemented in terms of bsd_glob(), but that would need to change a little bit.)
If changing what bsd_glob does is too great a break with bugwards compatibility, a new flag GLOB_CHECK (not present in FreeBSD or Linux) could be added to request the more consistent behaviour.
Perl Info
Flags:
category=library
severity=medium
module=File::Glob
Site configuration information for perl 5.18.4:
Configured by Red Hat, Inc. at Thu Apr 2 16:17:20 UTC 2015.
Summary of my perl5 (revision 5 version 18 subversion 4) configuration:
Platform:
osname=linux, osvers=3.19.1-201.fc21.x86_64, archname=x86_64-linux-thread-multi
uname='linux buildvm-23.phx2.fedoraproject.org 3.19.1-201.fc21.x86_64 #1 smp wed mar 18 04:29:24 utc 2015 x86_64 x86_64 x86_64 gnulinux '
config_args='-des -Doptimize=-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4 -grecord-gcc-switches -m64 -mtune=generic -Dccdlflags=-Wl,--enable-new-dtags -Dlddlflags=-shared -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4 -grecord-gcc-switches -m64 -mtune=generic -Wl,-z,relro -Dshrpdir=/usr/lib64 -DDEBUGGING=-g -Dversion=5.18.4 -Dmyhostname=localhost -Dperladmin=root@localhost -Dcc=gcc -Dcf_by=Red Hat, Inc. -Dprefix=/usr -Dvendorprefix=/usr -Dsiteprefix=/usr/local -Dsitelib=/usr/local/share/perl5 -Dsitearch=/usr/local/lib64/perl5 -Dprivlib=/usr/share/perl5 -Dvendorlib=/usr/share/perl5/vendor_perl -Darchlib=/usr/lib64/perl5 -Dvendorarch=/usr/lib64/perl5/vendor_perl -Darchname=x86_64-linux-thread-multi -Dlibpth=/usr/local/lib64 /lib64 /usr/lib64 -Duseshrplib -Dusethreads -Duseithreads -Dusedtrace=/usr/bin/dtrace -Duselargefiles -Dd_semctl_semun -Di_db -Ui_ndbm -Di_gdbm -Di_shadow -Di_syslog -Dman3ext=3pm -Duseperlio -Dinstallusrbinperl=n -Ubincompat5005 -Uversiononly -Dpager=/usr/bin/less -isr -Dd_gethostent_r_proto -Ud_endhostent_r_proto -Ud_sethostent_r_proto -Ud_endprotoent_r_proto -Ud_setprotoent_r_proto -Ud_endservent_r_proto -Ud_setservent_r_proto -Dscriptdir=/usr/bin -Dusesitecustomize'
hint=recommended, useposix=true, d_sigaction=define
useithreads=define, usemultiplicity=define
useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=undef
use64bitint=define, use64bitall=define, uselongdouble=undef
usemymalloc=n, bincompat5005=undef
Compiler:
cc='gcc', ccflags ='-D_REENTRANT -D_GNU_SOURCE -fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64',
optimize='-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4 -grecord-gcc-switches -m64 -mtune=generic',
cppflags='-D_REENTRANT -D_GNU_SOURCE -fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include'
ccversion='', gccversion='4.8.3 20140911 (Red Hat 4.8.3-7)', gccosandvers=''
intsize=4, longsize=8, ptrsize=8, doublesize=8, byteorder=12345678
d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=16
ivtype='long', ivsize=8, nvtype='double', nvsize=8, Off_t='off_t', lseeksize=8
alignbytes=8, prototype=define
Linker and Libraries:
ld='gcc', ldflags =' -fstack-protector'
libpth=/usr/local/lib64 /lib64 /usr/lib64
libs=-lresolv -lnsl -lgdbm -ldb -ldl -lm -lcrypt -lutil -lpthread -lc -lgdbm_compat
perllibs=-lresolv -lnsl -ldl -lm -lcrypt -lutil -lpthread -lc
libc=, so=so, useshrplib=true, libperl=libperl.so
gnulibc_version='2.18'
Dynamic Linking:
dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,--enable-new-dtags'
cccdlflags='-fPIC', lddlflags='-shared -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4 -grecord-gcc-switches -m64 -mtune=generic -Wl,-z,relro '
Locally applied patches:
Fedora Patch1: Removes date check, Fedora/RHEL specific
Fedora Patch3: support for libdir64
Fedora Patch4: use libresolv instead of libbind
Fedora Patch5: USE_MM_LD_RUN_PATH
Fedora Patch6: Skip hostname tests, due to builders not being network capable
Fedora Patch7: Dont run one io test due to random builder failures
Fedora Patch9: Fix find2perl to translate ? glob properly (RT#113054)
Fedora Patch10: Update h2ph(1) documentation (RT#117647)
Fedora Patch11: Update pod2html(1) documentation (RT#117623)
Fedora Patch12: Disable ornaments on perl5db AutoTrace tests (RT#118817)
Fedora Patch14: Do not use system Term::ReadLine::Gnu in tests (RT#118821)
Fedora Patch15: Define SONAME for libperl.so
Fedora Patch16: Install libperl.so to -Dshrpdir value
Fedora Patch18: Fix crash with \\&$glob_copy (RT#119051)
Fedora Patch19: Fix coreamp.t rand test (RT#118237)
Fedora Patch20: Reap child in case where exception has been thrown (RT#114722)
Fedora Patch21: Fix using regular expressions containing multiple code blocks (RT#117917)
Fedora Patch22: Create site paths by cpan for the first time (CPAN RT#99905)
Fedora Patch200: Link XS modules to libperl.so with EU::CBuilder on Linux
Fedora Patch201: Link XS modules to libperl.so with EU::MM on Linux
@INC for perl 5.18.4:
/home/eda/lib/perl5/
/home/eda/lib64/perl5/
/usr/local/lib64/perl5
/usr/local/share/perl5
/usr/lib64/perl5/vendor_perl
/usr/share/perl5/vendor_perl
/usr/lib64/perl5
/usr/share/perl5
.
Environment for perl 5.18.4:
HOME=/home/eda
LANG=en_GB.UTF-8
LANGUAGE (unset)
LC_COLLATE=C
LC_CTYPE=en_GB.UTF-8
LC_MESSAGES=en_GB.UTF-8
LC_MONETARY=en_GB.UTF-8
LC_NUMERIC=en_GB.UTF-8
LC_TIME=en_GB.UTF-8
LD_LIBRARY_PATH (unset)
LOGDIR (unset)
PATH=/home/eda/bin:/home/eda/bin:/usr/local/bin:/usr/bin:/sbin:/usr/sbin:/sbin:/usr/sbin
PERL5LIB=/home/eda/lib/perl5/:/home/eda/lib64/perl5/
PERL_BADLANG (unset)
SHELL=/bin/bash
--
Ed Avis <[email protected]>
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From @ap
* Ed Avis <perlbug-followup@perl.org> [2015-05-13 14:25]:
While this is consistent with Perl's builtin glob(), it seems inconsistent with File::Glob's documentation and with the FreeBSD glob(3) it purports to implement - at least as far as I can tell from for example <https://www.freebsd.org/cgi/man.cgi?query=glob&sektion=3>.
Within an empty directory the attached C program yields the following output on my FreeBSD box:
(no flags) x: No such file or directory
(GLOB_NOCHECK) x: x
(no flags) x*: No error: 0
(GLOB_NOCHECK) x*: x*
From @ap
#include <stdio.h>
#include <glob.h>
void
print_glob (char * description, char * pattern, int flags)
{
glob_t g;
int i;
printf("\n(%s) %s:\n", description, pattern);
if (glob(pattern, flags, NULL, &g))
return (void) perror("");
for (i = 0; i < g.gl_pathc; ++i)
printf("%s\n", g.gl_pathv[i]);
}
int
main ()
{
print_glob("no flags", "x", 0);
print_glob("GLOB_NOCHECK", "x", GLOB_NOCHECK);
print_glob("no flags", "x*", 0);
print_glob("GLOB_NOCHECK", "x*", GLOB_NOCHECK);
}
From @epa
Thanks for the test program. But I think it is missing the fact that (according to my reading of the FreeBSD manual page) the glob() function always sets the array of results, even if there was an error. Only the GLOB_ERR flag or a callback error handler will make it abort on error.
Please try this expanded test program:
#include <stdio.h> #include <glob.h>
void print_glob (char * description, char * pattern, int flags) { glob_t g; int i;
printf("\n(%s) %s:\n", description, pattern);
if (glob(pattern, flags, NULL, &g)) (void) perror(""); else puts("no error from glob");
printf("%d results returned\n", g.gl_pathc); for (i = 0; i < g.gl_pathc; ++i) printf("result %d: %s\n", i, g.gl_pathv[i]); }
int main () { print_glob("no flags", "x", 0); print_glob("GLOB_NOCHECK", "x", GLOB_NOCHECK); print_glob("no flags", "x*", 0); print_glob("GLOB_NOCHECK", "x*", GLOB_NOCHECK); }
-- Ed Avis <eda@waniasset.com>
From @epa
Please could I ask the perl5-porters to have another look at this bug?
As this bug was originally filed against an older perl version, I checked it with a somewhat newer one. Using 5.26.3 I can still reproduce the same behaviour:
% perl -MFile::Glob -E 'say File::Glob::bsd_glob("x")'
x
and the File::Glob documentation still says
GLOB_NOCHECK If the pattern does not match any pathname, then bsd_glob() returns a list consisting of only the pattern.
So I believe the behaviour is still inconsistent with the documentation (which at least implies that if GLOB_NOCHECK is not given then you will not get the pattern back on no match).
The C test program I suggested
#include <stdio.h>
#include <glob.h>
void
print_glob (char * description, char * pattern, int flags)
{
glob_t g;
int i;
printf("\n(%s) %s:\n", description, pattern);
if (glob(pattern, flags, NULL, &g))
(void) perror("");
else
puts("no error from glob");
printf("%d results returned\n", g.gl_pathc);
for (i = 0; i < g.gl_pathc; ++i)
printf("result %d: %s\n", i, g.gl_pathv[i]);
}
int
main ()
{
print_glob("no flags", "x", 0);
print_glob("GLOB_NOCHECK", "x", GLOB_NOCHECK);
print_glob("no flags", "x*", 0);
print_glob("GLOB_NOCHECK", "x*", GLOB_NOCHECK);
}
produces these results on Linux 4.18 with glibc 2.28:
(no flags) x:
No such file or directory
0 results returned
(GLOB_NOCHECK) x:
no error from glob
1 results returned
result 0: x
(no flags) x*:
No such file or directory
0 results returned
(GLOB_NOCHECK) x*:
no error from glob
1 results returned
result 0: x*
Note the first case, where the pattern did not match, GLOB_NOCHECK was not set, and the result from glob() was a zero return value, setting errno, and no results returned. I believe File::Glob's behaviour is inconsistent not only with its own docs, but with C glob().
